Valid domains are "system", "local", "network" and "user".
Domains can also
be specified using only the first letter.

Paths are searched for applications to register with the Launch Service database. The Launch Service database controls the Finder's 'Open With' right click, contextual menu.

After running lsregister to rescan the database or create a new UTI, run killall Finder to reload the Finder's “Open With” Menu, or just restart the machine.

Full Path to lsregister

lsregister is not on the system path so either:

Create an alias 'lsr' for the full path to lsregister:lsr='/System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/LaunchServices.framework/Versions/A/Support/lsregister

or temporarily add the directory to your PATH so that you can run lsregister with just lsregisterPATH=/System/Library/Frameworks/CoreServices.framework/Frameworks/LaunchServices.framework/Support:"$PATH"

Resetting the system will also reset the first-launch security prompt: the first time you launch an application by opening a document, the system will ask 'are you sure'.
This is equivalent to deleting the Launch services plist:~/Library/Preferences/com.apple.LaunchServices.plist

“Because the people who are crazy enough to think they can change the world, are the ones who do” ~ Apple Advert

Related:

Onyx utility - Includes a maintenance script to rebuild the Launch Services.Article: TA24770 - Clear the 10.4 Finder "Open With" contextual menu.StackExchange - How can I make macOS recognize new file extensions?